CHAPTER VIII. 
VARIETIES OF WING AND OF FLIGHT. 
CURVE—NARROW AND BROAD WINGS—STYLES OF FLIGHT— 
FLIGHT IN FLOCKS—THE WHIR OF WINGS. 
Curve. Narrow and Broad Wings. 
I shall first consider the question of curve, or, as 
the aviators call it, of camber—a question of the 
utmost importance. The wings of all birds are a 
good deal curved from front to back, so that as they 
descend they catch the air in a concavity and have 
plenty of lifting power. In some birds the front-to- 
back curve extends throughout the whole length of 
the wing, though in all there is some shallowing 
towards the tip. The Jay and the Red-legged 
Partridge (and their allies) supply good examples of 
a curve that shallows near the tip of the wing but 
does not disappear. Ina Jay, of whose wings I made 
measurements, the depth of the curve—measured 
just on the near side of the starting-point of the 
bastard-wing—was 1 inch (see Pl. xv and also xu 
and xiv). The breadth of the wing at this point 
was 52 inches. ‘Thus the curve is 1 in 53, a curve 
such as no aviator would ever think of using. But 
it must be remembered that during the down-stroke 
it is much reduced by the pliancy of the feathers, 
which yield to the pressure of the air. The span 
